The Bright Messenger by Algernon Blackwood

To Edward Fillery, the deep pain of frustration baffling all his mental processes, the end had come with a strange, bewildering swiftness. He knew there had been a prolonged dislocation of his being, possibly, even a partial loss of memory with regard to much that went on about him, but he could not, did not, admit that no value or reality had attached to his experiences. The central self in him had projected a limb, an arm, that, feeling its way across the confining wall of the prison house, groping towards an unbelievably wonderful revelation of new possibilities, had abruptly now withdrawn again. The dissociation in his personality was over. He was, in other words, no longer aware of "N. H." Like Devonham, he now did not "perceive" "N. H.," but only LeVallon. But, unlike Devonham, he "had" perceived him.

He had met half-way a mighty and magnificent Vision. Its truth and beauty remained for him enduring. The revelation had come and gone. That its close was sudden, simple, undramatic, above all untheatrical, satisfied him. "N. H." had "escaped," leaving the commonplace LeVallon in his place. But, at least, he had known "N. H."